I could not enter prior payroll tax info for a empployee. keep reset to zero, try more than 20 times

Let me help you with entering your employee's prior payroll tax information, jgao_nj.

We can try signing in to QuickBooks Online (QBO) using a private or incognito window. This mode doesn't use the existing cache data and helps us confirm browser-related issues. Here's how:

• For Google Chrome browser: Ctrl + Shift + N
• For Mozilla Firefox browser: Ctrl + Shift + P
• For Safari browser: Command + Option + P

Then, try entering the prior payroll again. The ability to enter historical payroll information is only available for the current calendar year and there are no paychecks created for the employee(s) yet. Here's how:

1. In QuickBooks Online (QBO), go to the Workers menu at the left pane to get to the Employees page.
2. Select the employee to open the information, then Enter prior pay details. 
3. Enter the necessary information.

For more information about the process, see the Set up a prior payroll article. If it works, go back to your regular browser and clear the cache to delete those temporarily stored files and browsing history. The overtime collection of data can create corruption, however, removing this should fix the issue. You can also use other supported, up-to-date browsers to roll out the possibility of a browser-related issue. 

On the other hand, if you already have paychecks created, I highly suggest contacting our Payroll Support Team. They have the tools that can help you enter the information. You may send a message via chat, call us at a time convenient to you, or we’ll get in touch with you instead. To ensure we address your concern, our representatives are available from 6:00 AM to 6:00 PM on weekdays and 6:00 AM - 3:00 PM on Saturdays, PST. See our support hours and types for more details about this one. 

Feel free to visit our Process payroll page for more insights about running and managing payroll in QuickBooks.

I'd like to know how you get on after performing the steps or contacting our support, as I want to ensure this is resolved for you. Please reply to this post and I'll get back to you. Take care always.